<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

<form th:action="@{http://localhost:8080/user/update}" method="post" th:object="${user}">
    <input type="hidden" name="_method" value="put">
    <input type="hidden" name="id" th:value="*{id}">
    姓名:<input name="name" th:value="*{name}"><br/>
    年龄:<input name="age" th:value="*{age}"><br/>
    性别:<input name="gender" th:value="*{gender}"><br/>
    <input type="submit" value="修改">

</form>

</body>
</html>